The long term objectives of the proposal are to: (a) empirically investigate the internal and external validity of an ecological approach to behavioral family intervention that seeks to transform coercive parent-child relationships into constructive relationships in the context of valued family routines; and (b) investigate the construct validity of the Parent and Child Coding System (PACCS) for reliably and accurately measuring both coercive and constructive processes of parent-child interaction in family routines. The specific aims are to: (a) conduct a longitudinal, experimental, single-subject analysis of the ecological approach to behavioral family intervention with twelve families of children with developmental disabilities and severe problem behaviors; (b) use PACCS to measure both coercive and constructive processes; (c) evaluate the efficacy of the approach for improving child behavior and parent-child interaction in the context of valued family routines; (d) assess the long-term durability of improvements; and (e) assess changes in global family functioning pre- to post-intervention. Twelve families of children with developmental disabilities and problem behaviors will participate in the study. For each family, four routines in the home and/or community will be selected for intervention. A single-subject, multiple baseline design across settings for each family will assess the functional relationship between implementation of the approach and changes in: (a) rate of problem behavior; and (b) successful completion of routines. Follow-up data gathered up to 24 months postintervention will provide descriptive data on the maintenance of intervention outcomes. Multivariate statistics will be used to evaluate the extent to which coercive processes have been transformed into constructive processes when comparing baseline to intervention and follow-up phases. The concurrent validity of the approach will be assessed through a multivariate analysis of changes in parenting stress, social support, and locus of control across baseline, intervention, and follow-up phases